Quad/OE Vacuum piping for the BOV

Trondelond

Active Member
I was looking at the other site, and noticed someone debating using the four vacuum outlets (or inlets, depending on your point of view) of the throttle bodies as opposed to the OE vacuum hose for the BOV.

What difference will this make exept for having some shiny samco vacuum hose running across the throttlebodies? Enlighten me.
 

PobodY

Moderators
Staff member
You can always daisy-chain them together with blue hoses that don't go anywhere. Surely that has the same effect as capping them all anyway.
 

MarkTurbo

Well-Known Member
Odin said:
I had my caps glued and cable tied on and they still got blown off, So their must be a fair bit of boost pressure hitting them at some point in the rev range, If it can blow the caps off I'd be worried about damaging the bov or fuel pressure regulator if I had them plumbed in to one of those four outlets.
I take it you dont know how a fuel pressure regulator works then :lol:
 

Trondelond

Active Member
PobodY said:
You can always daisy-chain them together with blue hoses that don't go anywhere. Surely that has the same effect as capping them all anyway.
And risk being caught with meaningless bling? I think not. The Skunk2 reservoir covers I threw on will have to do. 8)
 
As long as these are a take-off from behind the butterflies, surely its an idea place to run a pipe for the BOV. It will be under vacume when off throttle and it will be under pressure when on throttle. Thats exactly what you want on a BOV, its how they work.......isn't it??
 
Odin said:
They are not always under vacuum mate that's why the caps keep getting blown off the cars running higher boost, So of no use as a vacuum take off in my opinion.
Rob
You don't want them under vaccume all the time, only when off boost so the vaccume overcomes the spring tension in BOV, and the boost then escapes. When on throttle the vaccume pipe going to BOV has to equal the boost pressure to keep BOV closed?
Thats what i thought anyway lol.
I only question you because im looking to do this mod myself so need to know i am right lol
 
Last edited:

ashills

Active Member
yep always used the pipes off the quads best way u can do it unless running a map sensor then sometimes the map sesnor can see each engine pulse so need to use a pot
 

Trondelond

Active Member
ashills said:
yep always used the pipes off the quads best way u can do it unless running a map sensor then sometimes the map sesnor can see each engine pulse so need to use a pot
So you're running this setup with basically four hoses to the BOV? And this has not given you any grief?
This makes me wonder why Odin has had trouble with a similar setup. Or when trying to use this setup, I didn't quite catch that.

And - why is this better, excactly?
 
Last edited:
i think odin just meant that when running much higher boost than standard the plugs can come off; which sounds very likely. If you quad them up though and secure the hoses nice and tight then i can't see any problems arising. Im going to do it at the weekend anyways.... worth a try. Im sure it would be ok 8)
I believe the standard hose going to the re-circ is taken from a take-off point on the bottom of the throttle bodies. As a result they get blocked up, i know mine has been for a year now. So the advantage from taking the hose from the 4 top inputs (as above) is they don't clog up.
 
Last edited:

Trondelond

Active Member
That's what I was thinking, but I don't really have everything clear when it comes to all the hoses. I suppose with my pathetic 1.25 bar and thorough securing it should work fine. Woohoo! More coloured hoses! Thanks! :D

Oh, and 5-6mm inner diameter should work well on these little nipples, and on my HKS BOV?
 
Works a treat, i did this at the weekend and now my BOV works fine. The car seems to tick over a lot smoother now and sounds better... wierd :s
 
Top